1. Field of the Invention
The present invention relates to tuners receiving a plurality of broadcasting stations, and also to audio systems reproducing signals from a plurality of program sources such as tape-deck, tuner, etc.
2. Description of Background Information
There are broadcast stations in which pre-emphasis of a particular frequency range, a low frequency boost for example, is effected to the audio signal to be transmitted. In receiving and demodulating the broadcast wave from one of such stations by means of a tuner, it is necessary to adjust tone controls in order to obtain a flat frequency response. In the case of audio systems including components such as a tape-deck, a tuner, etc., the output signal level and frequency response can deviate among the components. With conventional audio systems in which the audio signal from a component is amplified in an amplifier to drive speaker systems, it is sometimes necessary to adjust the volume and tone controls in order to obtain a flat frequency response and the same signal level.
Therefore, manual operations for setting the frequency response are required, in the case of tuners, every time the receiving station is changed if broadcasting stations have different transmission characteristics of the audio signal, and in the case of audio systems, every time the selection of the component is changed. The requirement of such manual operations has been causing inconveniences in the operation of tuners or audio systems.